Extensor Carpi Radialis Longus

Definition

The extensor carpi radialis longus is a muscle in the posterior compartment of the forearm that extends and abducts the wrist. It is one of the key muscles involved in the movements of the pectoral girdle and upper limbs.

5 Must Know Facts For Your Next Test

1. The extensor carpi radialis longus originates on the lateral supracondylar ridge of the humerus and inserts on the base of the 2nd metacarpal bone.
2. It is innervated by the radial nerve, which is derived from the posterior cord of the brachial plexus.
3. The extensor carpi radialis longus works with the extensor carpi radialis brevis to extend and abduct the wrist, which is important for many upper limb movements.
4. Weakness or paralysis of the extensor carpi radialis longus can lead to impaired wrist extension and difficulty with activities requiring wrist stabilization.
5. The extensor carpi radialis longus is one of the muscles that can be palpated on the posterior aspect of the forearm when the wrist is extended against resistance.

Review Questions

• Describe the primary actions and functions of the extensor carpi radialis longus muscle.
  • The extensor carpi radialis longus is responsible for extending and abducting the wrist joint. This movement is crucial for many upper limb activities, such as grasping objects, writing, and manipulating tools. The muscle works in conjunction with the extensor carpi radialis brevis to stabilize the wrist during these functional movements. Additionally, the extensor carpi radialis longus can be palpated on the posterior forearm when the wrist is extended against resistance, making it an important landmark for physical examination and assessment of upper limb function.
• Explain the anatomical features and innervation of the extensor carpi radialis longus muscle.
  • The extensor carpi radialis longus originates on the lateral supracondylar ridge of the humerus and inserts on the base of the 2nd metacarpal bone. This muscle is part of the posterior compartment of the forearm and is innervated by the radial nerve, which is derived from the posterior cord of the brachial plexus. The radial nerve innervation allows for coordinated extension and abduction of the wrist, which is essential for many upper limb functions. Understanding the precise anatomical location and innervation of the extensor carpi radialis longus is crucial for evaluating and treating any neuromuscular or musculoskeletal conditions affecting this muscle and its associated movements.
• Analyze the clinical significance of the extensor carpi radialis longus muscle and the potential consequences of its dysfunction.
  • The extensor carpi radialis longus plays a vital role in maintaining proper wrist function and stability during upper limb activities. Weakness or paralysis of this muscle can lead to impaired wrist extension and abduction, which can significantly impact an individual's ability to perform tasks requiring wrist stabilization, such as grasping objects, writing, and using tools. This can result in decreased manual dexterity and reduced independence in activities of daily living. Additionally, the extensor carpi radialis longus is an important landmark for physical examination, as its palpation can provide valuable information about neuromuscular function and the integrity of the radial nerve. Understanding the clinical significance of this muscle and the potential consequences of its dysfunction is crucial for healthcare professionals in developing effective treatment and rehabilitation strategies for patients with upper limb disorders.

Related terms

Extensor Carpi Radialis Brevis: Another muscle in the posterior compartment of the forearm that also extends and abducts the wrist, but is shorter than the extensor carpi radialis longus.

Extensor Digitorum: A muscle that extends the fingers and is also part of the posterior compartment of the forearm.

Abduction: The movement of a limb or body part away from the midline of the body.